Internal combustion engine



Oct. 18, 1932. E. SCHIMANEK INTERNAL COMBUSTION ENGINE Filed Sept. 17.1928 4 Sheets-Sheet 1 Oct. 18, 1932.

E. SCHIMANEK INTERNAL COMBUSTION ENGINE Filed Sept. 1'7, 1928 4Sheets-Sheet 2 Oct. 18, 1932. E. SCHIMANEK 1,382,970

INTERNAL COMBUSTION ENGINE 7 Filed Sept. 17. 1928 4 Sheets-Sheet 3 Oct.l8,' 1932. E. SCHIMANEK 7 INTERNAL COMBUSTION ENGINE Filed Sept. 17.1928 4 sheets-sheet 4 v5 I1: 7 Kiwi Sam/mafia?- Patented Oct. 18, 1932Application filed Sept r OFFICE EHIL SOHIIANEK, BUDAPEST, HUNGARYINTERNAL comaus'rroN ENGINE i This invention relates to internal combus-:ion engines working on the four-stroke cycle,

- or on "a cycl strokes,

e' comprising more than four such for example as a six-stroke or aneight-stroke c cle.

The object of t e invention is to increase the .power of such internalcombustion engines,

and moreover to render the internal combustion engine capable of beingrun at will on a cycle comprising a different number of strokes,

as for example running a four-stroke engine as a two-stroke engine orrunning a sixstroke engine as a engine and so on.

nal combustion en two-stroke or a four-stroke The capacity of anintergine to run with different numbers of strokes per cycle provides inthe first place a means of utilizmg the advantages presented by amulti-stroke engine as regards excess power and fuel introduction, aswell as atomization, and particularly at high speeds in this lastrespect, and of changmg over to the two-stroke cycle or to a cyclecomprising a small loads at which such number of strokes at those acycle presents advantages, and thereby using the best attainable workingconditions. capacity provides a starting of four-st gines by starting tand then changing this changing over efi'ected The method of graduallyor'in stages which normallyrun more than four strokes.

On the other hand this means of facilitating the roke and multi-strokeenhem as two-stroke engines over to the normal cycles, to the normalcycles eing in engines on a cycle comprising working according to thepresent invention consists in the fact that the working cylinder, at theend of the com-- bustion stroke, as

in a two-stroke engine, is

scavenged and filled with fresh air produced by a charge compressor,

and this air filling forms part of the combustion air in the normalworking cycle The method or working according to the invention is suchthat in the working cylinder, strokes following at the end of theoutward the combustion stroke, or

ing cylinder with free .whereby this ember 17, 1928,8er1al No. aoasoo,an in Austrla October 4, 1927. y

at least at the end of the last of'these strokes,

fresh air'ls introduced by a charge compressor,-which also scavenlgesand fills the workcombustion stroke, as in the case of a twostrokeengine. The working process acc0rding to the invention has theresult,'for a fourstroke or multi-stroke engine, uses more air than atwo-stroke en ine,where by the invention presents a simp e means ofincreasing the power of multi-stroke engines. This increase of power isgreater than would correspond two-stroke engine, for in the case of atwo- Stroke engine a portion of the charging air is scavenged out withthe combustion gases,

portion is lost so far as the output of work is concerned. This actiononl occurs, with the process according to this invention, at the firstfilling, which forms a portion of the total filling when working on afour-stroke or multi-stroke cycle, but not in the case of the subsequentfillings or chargings of the working cylinder, which form the remainderof the total filling, so that in the case of the admissions of air areprevented. The power output .can be still further increased according tothe invention by also utilizingv the working piston invention he airdelivered in partial quanti-- that the engine following the first ad- 1mission, losses of work resulting from losses .air at the end of theproportionally to the power of a ties in a plurality of strokesof oneworking cycle by the, charge compressor either alone or in combinationwith air suction into the working cylinder can be utilized in its entirety uring one stroke, namely the combustion stroke, for theperformance'of work.

Various constructional forms of the resent invention are illustrated byway 0 ex- I cylinder, and 8 the overflow or relief valve,

ample in the accompanying drawings, in

which 7 Fi s. 1 to 3 show three difierent construction forms of anengine according to theinvention Fig. 4 shows a diagram of the engineillustratled in Fig. 1 when working on a six-stroke c c e Fig. 5 showsthe diagram of the engine illustrated in Fig.1, when the engine is onlyworking with the air produced by the compressor,

Fi 6 shows a constructional form in whic the working cylinder is onlycharged with air which is sup lied by the air pump,

Figs. 7 and 8 in icate the variation of pressure in the working.cylinder of the engine illustrated in Fig. 6,

Fi 9 shows a constructional form in whic the air employed for combustionin the working cylinder is delivered both by air suction into theworking cylinder and by means of the charging air pump,

Fig. 10 shows a constructional example in which the working cylinder andthe charging air pumpl have an air-suction valve in common, an Figs. 11aand 11b show a detail device of the valve gear.

In the constructional example shown in Fig. 1, 1 is the workingcylinder, 2 the working piston, 3 the complresssor cylinder, 4 thecompressor piston, 5 t e suction valve of the compressor, 6 thedeliveryvalve of the compressor, 7 the exhaust valve of the working from theworkingcylinder to a vessel 9 or conversely. The compressor is connectedwith the workin cylinder by a pipe 12 connected to the delivery valve 6.

The working cylinder has a suction valve 19, in addition to the valves 7and 8 illustrated in the figure. A needle valve 10 serves for theintroduction of fuel into the working cylinder.

A motor constructed according to this example can" workby the two-strokecycle or by the four-stroke cycle, or even by the sixstroke or othermulti-stroke cycle, according to the position of the valve gear.

Hence the method of working is dependent upon the number of strokes withwhich the working cylinder is designed to work.

, When workin on the two-stroke cycle the rocedure is as ollows theworking piston escends from its upper dead centre, while i thecompressor piston is likewise moving downwards-tram its upper deadcentre.

. compressed,

' f stroke,'is expelled throufgh the delivery valve 6 into thetub'e .12.Be 05 In the working cylinder combustion and ex ansion takes placeduring this stroke, while 1n the compressor cylinder the air is andtowards the, end of the h ore the working piston opens the ports 11 inthe cylinder wall the exhaust valve 7 is opened, so that the combustiongases are expanded. After the opening of the cylinder port 11, air flowsfrom the compressor or from the tube 12 through the delivery valve 6 andthe connecting tube 12 through the ports 11 into the working cylinderand forces the expanded combustion gases that still remain thereinthrough the exhaust valve ,7 into the open. During the next stroke'thepiston 2 ascends. In the working cylinder compression takes place. Atthe same time the piston 4 likewise moves upwards and draws in fresh airthrough the suction valve 5. Hence when working on the two-stroke cyclethe suction valve, of the working cylinder, does not come into action atall and accordingly onlythat quantity of air which is delivered by thecompressor is dealt with in the working cylinder.

The working of the same motor on the sixstroke cycle for exampleproceeds as follows First stroke: The piston of the working cylinderdescends, and combustion and expansion occur in the cylinder. At thesame time the compressor piston descends and compresses the airpreviously drawn in by suction.

. In the neighbourhood of the lower dead centre, before the workingpiston opens the ports 11 in the cylinder wall, the exhaust valve 7 isopened and the combustion gases flow out of the working cylinder intothe at mosphere, andan expansion of these gases takes place in thecylinder. Just after this the ports l'lare opened by the piston 2,whereby air fiows through these ports into the working cylinder andclears the latter of the combustion gasesf Second stroke: The pistonsQ'and 4 move upwards; and in the working cylinder compression takesplace. Since however towards the end of the stroke the overflow valve 8is opened, the compressed air is delivered into the reservoir 9.

During this stroke the compressor piston 4 draws in fresh air throughthe suction valve 5.

Third stroke: During the working movement theworking piston 2 drawsfresh air into theworking cylinder through thesuction valye, not shownin the figure, while the piston 4, which is likewise moving down wards,compresses'the air previously drawn closed, the piston 2 opens the ports11, and the air drawn in by. the working piston issupplemented by theair delivered by the compress'or and flowing in'through the ports 11-,the workin cylinder thus being supercharged by t e latter quantity ofair.

Fourth stroke: During this stroke, as" during the second stroke, the airin the working cylinder is forced into the reservoir 9 and fresh air isdrawn by suction into the com pressor. I

Fifth stroke: The details of this stroke are exactly the same as thoseof the third stroke.

Sixth stroke: The working piston 2 moves upwards and compresses the airto the desired extent (the extent of the precompression) which isdetermined by the portion of the stroke which the piston covers duringthis compression. This precompression may how'- ever be equal to zero ormay be omitted. After the precompression has been effected, or, in theevent of it being omitted, after ports 11 have been closed, the valve 8is opened. The air forced into the reservoir 9 during the two previouscharging strokes flows back into the working cylinder, so that thelatter is filled with a multiple, theoretically five-fold, of thatquantity of air which would fill it at atmospheric pressure. The valve 8is closed after being open for a suitable short time, and, during thefurther upward movement of the piston 2 effects the final compressionright to that terminal pressure at which combustion is to take place.

During this stroke the compressor piston 4 draws air by suction into thecompressor cylinder.

lVhen the motor is intended to work on the four-stroke cycle, the valves7 and 8 are so controlled that after the first and second strokes theprocedure that follows is the same as that described in the case of thesixstroke motor as the fifth and sixth strokes.

Hence it only depends upon the controlling of the valves illustratedwhether the motor works on the two-stroke, the four-stroke, thesix-stroke or other multi-stroke cycle By an adjustment, for instance alongitudinal displacement or any other convenient adjustment of the camshaft, the result can be obtained that the motor Works temporarily ondifferent cycles one after the other.

The pressuresoccurring in the working cylinder when the engine isworking on the six-stroke cycle are illustrated in Fig. 4 by recordingthe six strokes in succession on the abscissa axis, While the ordinatesrepresent the pressure prevailing in the working cylinder.

The temporary storage of the combustion air may also be effected in theworking cylinder. In this case the reservoir 9 and the valve 8 areomitted. As contrasted with the method of working previously describedin which not only the air drawn in by the compressor but also the airdrawn in by the working piston are used, in the case of the air beingstored in the working cylinder itself only the air delivered by thecompressor can be used, since in the working cylinder a greater pressureprevails during all strokes than the pressure of the externalatmosphere, so no suction of air can be effected.

the drawings, each The pressures prevailing in the working cylinder inthis caseare shown in Fig. 5 for an engine working on the six-strokecycle. Dur the individual successive strokes, the following changes ofcondition succeed one another Thirdstroke Expansion of the fillinguntil, with the exhaust valve opening of the takes place.

Fourth stroke: Compression of the double charge.

Fifth stroke: Expansion of the doubled charge, until, after the openingof the ports 11, the third charge takes place.

Sixth stroke Compression ofthe three-fold charge, at the end of suredesired for the combustion occurs.

This engine, like the engine previously described, can work on thetwo-stroke, fourstroke and six-stroke cycles, or on a cycle comprisingmore than six strokes, and the means necessary for altering the numberof strokes consists simply in the fact that the cam shaft is displacedor the exhaust valve and the fuel injection valve are opened in anyother way closed, after the ports, the second charging or thirdrevolution of the engine shaft. In Fig. 2 is illustrated by way ofexample a second constructional form of the invention.

The difference between this constructional form and Figure 1 consists inthe fact that here a differential piston 13 serves as a workhaust valve14 is arranged at the end of the stroke and is connected by ports withthe working cylinder space.

The valve 15 is the overflow valve to a reservoir 16. The needle valve17 serves for the introduction of the fuel.

In the rconstructional example illustrated in two cylinders providedwith cranks rotated through 180 degrees cooperate as illustrated in theFigure by the pipe connection 18. The reservoirs 16 pertaining to thetwo working cylinders may be con nected if desired.

The two methods of working described above in reference to Fig. 1(temporary storage of the air in structional example illustrated in-Fig.2m

In Fig. 3 is illustrated a further construcwhich the terminal presingand compressor piston, and that the exa vessel or in tlie workingcylinder itself) may also be embodied in the contional example, which isdistinguished from the one described above by the fact that the airsucked in by the working cylinder and the air after every revolution orafter every second working cylinder, combustion and expansion.

take place. In the compression cylinder compression and expulsion of theair through the pressure valve 24 into the vessel 21 take place.

Before the working piston 22 opens the ports 25 located at the lower endof the stroke in the side of the working cylinder, the exhaust valve 26is opened and the expansion of the combustion gases is effected. Justafter this, through the ports 25, when .the valve 27 opens, air is blownout of the vessel 21 into the working cylinder, whereby the workingcylinder is cleared of the combustion gases and filled with fresh air. I

Second stroke: Both pistons ascend. In the working cylinder the chargeis at first a little compressed and is then forced through the valve 28into the reservoir 20.

In the, compressor cylinder during th s stroke air is drawn in bysuction through the valve 29.

Third stroke: In the working cylinder, fresh air is drawn in by suctionthrough a suction valve not shown in the figure.

In the compressor the air is compressed and forced through the valve 24into-the reservoir 21.

Fourth stroke: In the working cylinder air is compressed as in thesecond stroke and forced into the vessel 20, while fresh air is drawninto the compressor cylinder by suction.

Fifth stroke: In the working cylinder and in the compressor cylinder thesame changes of condition occur as in the third stroke. As soon,however, as the working piston opens the ports 25 near the lower end ofits stroke, the valve 27 is opened, and the air forced into the vessel21 during the preceding compression strokes flows through this valve 27into the working cylinder, whereby the same is supercharged. 1

- Sixth stroke After the working piston during its ascent has closed theports 25, or if the charge has already beencompressed to the desiredextent by aifurth'er at vance of the pis- Lon, the working cylinder isplaced in communication with the vessel 20 by the opening of the valve28, whereby an equalization of pressure is produced, that is to say, theair forcedinto the vess l 20 during the preceding strokes flows backinto the working cylinder, thereby producing a further superchargingthereof.

After being open for a suitable time the valve 28 closes, and the entirecharge in the working cylinder is finally. compressed to the desiredcombustion pressure during the movement of the working piston right toits upper dead centre.

In Fig. 5 the variations of pressure occurring inthe working cylinderare shown in dotted lines.

The working processes described above can of course'be appropriatelycombined with one another.

By heating the reservoirs with the exhaust gases, the waste heat thatwould otherwise be lost can be conveyed into the preoompressed air andutilized for the performance of work. This heating can also be carriedout in the case of the temporary storage of air in the working cylinderitself, by ,means of heating surfaces arranged in the latter.

InFig. 6 is shown a constructional example in which the charging airpump delivers the 'air directly into a vessel in which the air from theworking cylinder can also be transferred from time to time for storagepurposes. The charging air is therefore in this case not supplied, aspreviously, through the working cylinder to the reservoir, but thereservoir is charged with air directly by the charging pump. 1

In the constructional example of Fig. 6, 31

is the cylinder, which is equipped with a cooling jacket 32, in whichfor example cooling water circulates, and 33 is the piston. The spaceabove the piston is the working cylinder space, and the space" below thepiston is the pump cylinder space. 38 is the suction valve and 37 thedelivery valve for the pump cylinder space. To the delivery valve 37 isconnected a pressure space or air reservoir for the pump consisting of atube 39 and an elbow l1, and communicating with the working cylinderspace by way of a valve 34 fitted into the cylinder head. The pressurespace or air reservoir is provided with a heating jacket 40, for thepurpose of enabling the air stored in the pressure space to be heated bymeans of the combustion gases for example if desired.

The cylinder 31 is provided at the bottom with an exhaust port 35, whichopens into a space in which'the exhaust valve 36 is arranged. I,

In Figs. 7 and 8 are shown thediagrams in which the variations ofpressure above the piston are plotted as ordinates, whereas the volumefor theindividual strokes I, II-I, II are plotted in succession asabscissae.

The method of working of this engine is as follows V 1 When the engineis. working on the twostroke. cyclethe. procedure is in accordance with'Fig. 7. Starting from the combustion and expansion stroke, which isrepresented in Fig. 7 by the line a, b, c, the introduction of the 'fueland the combustion take place above the piston during the descent of thepiston according to the line a, b, and the expansion of the combustiongases takes place according to the line b, 0, while underneath thepiston the 3 3 *ries of operations PIStOII, as with the two-strokecycle, fresh air is drawn place above the" piston according to the linec 4 H After this has occurred the valve 34 is opened and air flows outof the vessel 39 mto the cylinder and drivesthe products of combustionthat are still contained therein through the exhaust valve 36, which atthis time is still open, into the atmos here. In the diagram it isassumed that t is expulsion of the products of combustion is effectedduring the position of rest of the piston at the lower dead centre, sothis change of condition is included in the line 0, d.

Hereupon-both the exhaust valve36g and the valve 34 are closed, andthecompression of the charge of air is efiected above the pis ton duringthe ascent of the piston, whereas below the piston the suction of freshair is effected through" the suction valve 38. The change of conditionabove the piston is shown by the line (1, e.

The piston 33 must be made so long that the port 35, even in the highestposition of the piston, is not uncovered by the lower edge of t episton.

Dunn the next stroke the combustion is again e ected above the pistonaccording to the line e--b, then the expansionaccording to the line b'c'as previously described, and with this stroke the repetition of thesecommences. KR F g. 8 shows the method of working when operating on thesix-stroke cycle. In representing the variations in pressure a start isagain made with the combustion and expansion stroke, which roceeds inthe manner previously described At the lower dead centre of the pistonthere occurs, as in the previous case, first the valve 36 and then theex ulsion of the combustion products from t e c linder by the airflowing into the cylinder voir 39 through the valve 34.

The second stroke on the contrary proceeds differently from thetwo-stroke cycle, for at the dead centre only the valve 36 is closed,while the valve remains 0 en. During the ascent'ofthe piston, there ore,the air in the cylinder and in the space 39 connected therewith iscompressed (see line de), whereas below the previously described inconnection in by suction.

During the third stroke the piston moves downwards. The valve 34 isopen, so that air from the reservoir 39 flows back again into thecylinder. At the same time, underneath the piston, the air which wassucked in during the earlier stroke, is, delivered movement of thepiston,

exhaust through the romt ese" er r fline ),during the second stroke inthrough the delivery valve 37 into the reservoir 39.

Since the increase of volume, which is occasionedabove the piston by thedownward is of exactly the same magnitude as the decrease of volumeabove the piston, the line in the working diagram (marked 6- in thefigure) shows initiall a diminution of pressure, which lasts unti therising ressure in the pump chamber reaches the alling pressure in theworkmg chamber and then continues at constant K pressure. I

During the fourth stroke the air above the piston is forced through thestill open valve 34 into the reservoir 39 (the pressure line f-g) andfresh air piston.

is sucked in below the During the fifth stroke, the valve 34 still beingopen, the same chan e of condition takes) place as during the thirdstroke '(line 9 Now at the lower dead centre of the piston the valve 34is closed, and during the sixth stroke the air above the iston iscompressed according to the line --i, and below the piston fresh air isagain sucked in.

If the engine is workin on the four-stroke cycle, the first three stroes are the same as on the six-stroke cycle. Instead however of thecompression [g, which takes place in the fourth stroke 0 the six-strokecycle, a compression hc' occurs with the starting point f.

In the eight-stroke cycle, to the first five strokes described inconnection with the six- ,stroke cycle are added two additional strokes,which correspond to the fourth and fifth strokes in the six-strokecycle, and only then .valves 36 and 34 is suflicient to enable the motorto work on strokes.

a cycle of any number of In the two-stroke cycle the valve 34 alwaysremains open only during the shorttimeof the expulsion of the combustionproducts which time the valve 36 is also opened. I

In the four-stroke cycle the exhaust valve 36 is opened for a shorttimeonce after each four strokes at the dead centre of the piston, after theexpansion stroke, whereas the valve 34, which is likewise opened at thesame dead centre, remains open for the duration of two strokes, and isclosed again at the lower dead centre of the piston.

In the'six-stroke cycle the exhaust valve 36 is opened at the lower deadcentre after each six strokes and left open for a short time, as

when working on other cycles. 7 The valve 34 is opened as previouslyafter the expansion stroke at the lower dead centre of the piston andremains open for the duration 0 four strokes.

stroke both In the eight-stroke cycle the movement of the exhaust valveis effected after each eight strokes and the valve 34 remains open forthe duration of six strokes.

In the construction according to Fi 9, 42 is a suction valve and 36 anexhaust va ve for the working cylinder, while the remaining valves havethe same reference numerals as 1n Fig. 6.

The method of working is as follows: First stroke: If the iston 33,which acts as a compressor in the ower space and as a working iston invthe upper space, moves downwar s starting from its upper dead centre,there take place in the working cylinder space theinjection of fuel, thecombustion 'and the expansion, while in the pump chamber the air suckedin during the preceding stroke is forced through the pressure valve 37into the reservoir 39 which is common to the pump and the workingcylinder. At the lower dead centre the exhaust valve 36 opens, and anexpansion of the expanded combustion gases takes place. At the samemoment the valve 34 opens and the airflows out of the vessel 39 into theworking cylinder space and clears the latter "of the exhaust gases.

The rocedure during the following strokes depen s upon whether the motoris to work on a two-stroke cycle or on a cycle containing 'more than twostrokes.

In the two-stroke cycle after the end of the scavenging, and just afterthe lower dead centre position at the beginning of the second the valve36 and the valve 34 are closed, and compression takes place in the.working space right to the upper dead centre,

I while in the pump chamber air is sucked in its upper dead centre,

dead centre ""valve 10 into the working space begins and example, istonhas left the lower dead centre, that through the suction valve 38. Atthe upper the injection of fuel through the the series of operationsrecommences.

In working on a cycle comprlsing more than two strokes, on a six-strokecycle for in the second stroke, just after the the cylinder with airfrom the reservoir at .a higher pressure, which also has the advantagethat the loss of air that occurs during the expulsion is smaller, thatis, more air remains behind in the reservoir 39, and can then be usedfor the combustion. Under .these circumstances this pressure can beadhaust valve 36 justed either by hand or automatically by means of aregulator according to the speed of revolution of the motor for the timebeing, the exhaust being for example more severely throttled when thespeed of revolution is lower.

Third stroke: In the Working cylinder, after the valve 34 is closed atthe upper dead centre, air is drawn in by suction through a suctionva-lve42, while in the pumping space the compressed air is deliveredthrough the.

valve 37 into the reservoir 39.

Fourth stroke: The air in the working space, after the valve 42 isclosed at the lower dead centre, is compressed, and, after the openingof the valve 34', is forced into the reservoir 39, whereas in thepumping chamber air is again sucked in throu h the valve 38. Fifthstroke: In the working chamber, after the valve 34 is closed at theupper dead centre, air is drawn in through the suction valve 42, whereasin the pumping space compression takes place and transfer of the airthrough the valve 37 into the reservoir 39.

Sixth stroke: After the valve 42 is closed at the lower dead centre,just at the dead centre or else after the air in the working cylinderspace has been compressed to a certain extent, the valve 34 is opened,whereupon the air delivered into the reservoir 39 during the precedingstrokes flows into the working space. After this has occurred, that is,after the equalization of pressure between the working space and thereservoir has taken place, the valve 34 is closed, and there ensues inthe working cylinder, during'the further ascent of the piston right tothe end of the stroke, the final compression of the whole of thecombustion air. In the pumping space during this stroke, as in thefourth stroke, air is again sucked in through the valve 38. Then at theupperv dead centre the injection of fuel begins and the series ofoperations is repeated.

In Fig. 10 is illustrated a constructional example which isdistinguished from the ones previously described by the fact that theexployed which is common to the working space and the pumping space. Themethod of oper ation with this constructional example is as follows Whenworking on the two-stroke cycle the piston 33 moves downwards from itsupper dead centre during the first stroke. In the is arranged outsidethe working cylinder and a suction valve 42 is em-' working space theinjection of fuel takes place at the dead centre, and during the strokethe expansion of the combustion takes place. In the pumping chamber thedelivery of air is effected through the delivery valve 37 into thereservoir 39. When the upper edge of the workin piston uncovers theaperture 35 in the wor ing cylinder, the

exhaust valve 36 is opened either automatiworking space or positivelyby'a valve gear and an expansion of the combustion gases 7 recommencesand the series of the lower edge of the upper dead centre,

of the valve 42.

takes place in the working space. After this has occurred the valve 34is opened andthe air flows out of the reservoir 39 into the workingspace, driving the combustion gases before it, and the working cylinderis cleared of the combustion air. This filling of the working cylinderlasts until the piston 33 closes the port 35 during its ascent (secondstroke), after which the valve 34 is likewise closed. During the furthercourse of the second stroke, the air is finally compressed in theworking space. At the upper dead centre the injection of fuel operationsis repeated. During the second stroke, in consequence of the upwardmovement of the piston, a vacuum is produced in the pumping space, thedegree of which is enhanced until the piston 33 uncovers the port 35,and air flows into the pump space through the valve 42, an automaticValve for example, and equalizes the vacuum.

hen working onthe six-stroke cycle:

First stroke: The working piston moves downwards. After the injection offuel has commenced at the upper dead centre the expansion is effected,and, at the moment when the upper edge of the piston uncovers the port35, as in the case of the two-stroke cycle, the exhaust commences, and,after theopening of the "alve 34, the scavenging of the combustionproducts. It may be advantageous, during the exhaust, either by strongerspring loading of an exhaust valve, an automatically acting exhaustvalve for example, or by slighter opening of a mechanically controlledexhaust valve, to throttle the exhaust, and thereby to occasion thescavenging and filling of the cylinder from the reservoir at a higherpressure. In the pumping space compression and delivery of the air byway of the compression valve 37 into the reservoir 38 are effectedduring the first stroke.

Second stroke: Aftee the upper edge of the ascending piston has closedthe port 35, the air is transferred to the reservoir 39 through thevalve 34, which still remains open. During this stroke there arises inthe pumping space a vacuum, which, at the upper dead centre, after thelower edge of the piston has uncovered the port 35, is com ensated forby the air flowing in by way of t e valve 42*.

Third stroke: The valve 3-4 is closed at and while the piston isdescending a vacuum is produced in the working space, which, after theupper edge of the piston has uncovered the port 35, is compensated forby the air flowing in by way In the pumping space delivery of air iseffected gases and filled with fresh governor may shift the throughv thepressure alve 37 into the reservoir 39. 1 a

Fourth stroke: Inthe. working space COll1 ,pression is effected, and,after the valve 34 Inthe pumping space therearises a vaciscompensatedfor at the upper dead centre by the fresh charge of'a ir-flowing in.Fifthstroke: The same as the third stroke. Sixth stroke: After the upperedge of the piston has closed the port35, the valve34 is opened eitherjust after this or after the air in the work" during of pressure takesplace between the working space and the reservoir, the air delvered'intothe reservoir during the preceding strokes flowing into the workingspace. The'valve 341's then closed.- .Thereupon, during the remainder ofthe stroke,'is effected the final compression of the entire charge inthe worke pumping space there occurs "during this stroke a vacuum, whichis compensated for at the upper dead centre by the air flowing in by Wayof the valve 42 The changein the valve gear that is necessary for thechange in the cycle may be effected in Various ways, by shifting the camshaft for example. The alteration inthe valve gear may be effectedeither by handor automatically by a regulator, such'as a centrifugalgovernor. Thus for instance the engme may be started on the two-strokecycle, and, after a certain predetermined speed of revolution has beenattained. the'centrifugal valve gear to the the six-stroke cycle ingspace. In th four-stroke cycle, thento and finally to the 8-strokecycle, for the purpose of utilizing the known advantages offered bymulti-stroke cycles at rather high speeds, and atthe: same timefacilitating the starting. It may be mentioned that an engine working-ona multi-stroke cycle furnishes more power than when working on thetwo-stroke cycle, because the loss of .charg ng air duringscavengingoccurs, in the case of the two-stroke cycle, at every charge only occursfor that charge which is delivered by the pump and which scavenges thecombustion gases out of the cylinder, but not in the case of theremaining charges, which are stored from t me to time inthe reservoirand the cylinder.

Furthermore for a multi-stroke cycle. as described above, besides thethe pump, the air drawn by suction working space can also be used.

In Figures. 11a and llb'is illustrated by way of example a constructionby which the motor s enabled to be run on a cycle comprisin g either twoor four or six strokes, etc,'; that part of the valve gear being shownwhich into the is'opened, the air is driven into the reservoir 39. uum,which ng space has been compressed part of the'stroke, and anequalization air delivered by age charge charge toget quent changes ofactuates the outlet valve 36 or 36. A is the rod controlling themovementof the valve. This rod is provided with aroller B and is movedby the cams C or D or E according tol the position of the cam dsc Hwhich is shdablc on the cam shaft F. The cam disc is running with asixth of the number of turns of the motor, so that, when working on thetwostrokc, six cams E will be put into action durin one revolution ofthe cam shaft. If, however, the cam disc is displaced by means of thesliding ring G, so that the three cams C will come into action, theoutlet valve will be opened three times during one revolution of the camdisc, and the motor, therefore, will run on the four-stroke. And if thecams D are brought to action, of which cams there are two, the motorwill work on the sixstroke. I

The fuel valve is controlled in the same manner as the outlet valve bymeans of aslidable cam disc.

What I claim is 1. A method of operating internal combustion engines ofthe Diesel type working on a cycle comprising four or more strokes,characterized in that the power cylinder, at the turning of the strokeat the end of the combustion stroke, is (by means of a com-' pressor orthe like operated independently of the. ower cylinder piston) scaven 'edand with air to a degree alrea sufiicient for a ower stroke, and thattis air her with additional charging air the subsequent. strokes of suppied during the cycle is compressed in the power cylinder during itsinward stroke immediate y precedingtthe combustion.

2. ethod as set forth in claim 1, in which the supply fected not onl bpressor but a so y suction of air into the power cylinder. 3. Incombination, an internal combustion engine ofthe Diesel type comprisingfour or more strokes and having a cy inder with a piston reciprocablethere in, a chamber providing a reservoir compressor means operableindependent 0 the engine to supply compressed air to the reservoir,valve means to admit compressed air to the power c linder at the turningof the stroke at the en of combustion air is efworking on a cycle forair of the combustion stroke piston reci rocable therein, means tosupply compresse air to the cylinder to scavenge the cylinder and chargeit with air suflicient for a power stroke at the end of the combustionstroke, and means for supplyin' additional compressed air to thecylinder during subsequent strokes of the cycle, all the air chargesthus sup lied to the cylinder being compressed toget piston during theinstroke immediately preceding combustion.

In witness whereof I have hereunto signed my name.

EMIL SCHIMANEK.

ier in the cylinder by its delivery of air by a comand to charge thecylinder with air suflicient for a power stroke, means to admitsubsecompressed air into the power cylinder to be compressed by itspiston and'stored in the reservoir, and means to admit the stored airinto the Cpower cylinder to be compressed therein uring the inwardstroke of the piston immediately preceding combustion.

4. An internal combustion engine of the Diesel ty working on a cycle -offour or more stro es and having a cylinder with a

